Method of measuring temperature of a heated part

Abstract

A method of measuring temperature of a part heated during a heating process includes applying a non-reactive coating at a first temperature; heating the part, and thereby the coating thereon, to a second temperature greater than the first temperature; and measuring a temperature distribution of the part by measuring infrared light emitted from the heated coating using a thermal imaging device calibrated to the known emissivity of the coating. The coating is at least partially opaque and having a known emissivity of infrared light and conducts thermal energy from the underlying part.

The invention claimed is: 
     
       1. A non-destructive method of measuring temperature of a part heated during a heating process, the method comprising:
 applying a temporary, non-reactive coating to an outer surface of the part at a first temperature, the coating being at least partially opaque and having a known emissivity of infrared light, the coating being a thermal conductor having limited thermal insulating properties, the coating being a mineral powder coating which includes grains having a plurality of facets; 
 heating the part, and thereby the coating thereon, to a second temperature greater than the first temperature, the coating conducting thermal energy from the underlying part; 
 measuring a temperature distribution of the part by measuring infrared light emitted from the heated coating using a thermal imaging device calibrated to the known emissivity of the coating; and 
 removing the temporary, non-reactive coating from the part after determining the temperature distribution of the part. 
 
     
     
       2. The method of  claim 1 , wherein applying the coating onto the part comprises applying a totally opaque coating onto the part. 
     
     
       3. The method of  claim 1 , wherein applying the coating onto the part comprises applying a thin layer of the coating onto the part. 
     
     
       4. The method of  claim 1 , wherein applying the coating onto the part comprises applying a uniform layer of the coating onto the part. 
     
     
       5. The method of  claim 1 , wherein applying the coating onto the part comprises applying a talcum powder coating onto the part. 
     
     
       6. The method of  claim 1 , wherein applying the coating comprises applying a matte coating. 
     
     
       7. The method of  claim 1 , wherein removing the coating from the part comprises dusting off the coating. 
     
     
       8. The method of  claim 1 , wherein applying the coating onto the part comprises spraying the coating onto the part. 
     
     
       9. The method of  claim 8 , wherein spraying the coating onto the part comprises spraying a mixture of dispersive liquid and powder of the coating. 
     
     
       10. The method of  claim 1 , wherein applying the coating comprises applying the coating having a known emissivity higher than an emissivity of the part. 
     
     
       11. The method of  claim 1 , wherein applying the coating comprises applying the coating having a known emissivity of at least 0.95. 
     
     
       12. The method of  claim 1 , further comprising identifying areas of a surface of the part having a temperature above a predetermined temperature after determining the distribution of temperature of the part. 
     
     
       13. A method of controlled heating of a part, the method comprising:
 heating the part using a heating process; 
 measuring the temperature of the part as defined in  claim 1 ; 
 identifying local hot areas of a surface of the part having a temperature above a predetermined third temperature, the third temperature being higher than the second temperature; and 
 connecting a localised temperature measuring device to the surface of the part at the identified local hot areas. 
 
     
     
       14. The method of  claim 13 , further comprising heating the part to a temperature below the third temperature after connecting the localised temperature measuring device to the identified local hot areas. 
     
     
       15. The method of  claim 14 , wherein heating the part at a temperature below the third temperature comprises induction heating the part. 
     
     
       16. The method of  claim 15 , further comprising removing the coating from the part.